Transformer core mounting



Jan. 11, 1955 v. H. MASSAR 7 2,699,531 TRANSFORMER CORE MOUNTING FiledSept. 2, 1950 5 III 'I Q l5 J. --|5 l4 n r; L44

9 W x\ 26 2e 25 \Q /z4 INVENTOR. VAL H. MASS/4R BY ATTORNEY UnitedStates Patent ()fifice P atented Jan. 11, 1955 TRANSFORMER CORE MOUNTINGVal H. Massar, Jersey City, N. J., assignor to Bendix AviationCorporation, 'Teterboro, N. J., a corporation of Delaware ApplicationSeptember 2, 1950, Serial No. 182,986

7 Claims. (Cl. 336-92) This invention relates to transformers and, moreparticularly, to mountings for transformer cores.

In mounting transformer cores in a casing, it is customary to secure thecore of the laminated type to a bracket by screws or rivets and thensecure the bracket to the casing by bolts, or other similar fasteningmeans. In practice, this manner of assembly is time consuming andincreases the work and cost of the individual transformer units byincreasing the number of operations expended thereon. A second method ofassembly has been proposed wherein the transformer core is fitted into aflanged bracket and the bracket itself is secured to the walls of acasing by means of tongues or depressions formed in. the casing. Thislast method of assembly is also disadvantageous because .each casingmust be specially constructed and fitted. within close tolerances to theindividual transformer cores, ultimately increasing the costs ofmanufacture.

In cases where the sizeand weight of the transformer unit is animportant factor, .present transformers are disadvantageous insofar asthey are bulky and heavy. Weight is important when transformers are:used on aircraft. Where a plurality of transformers areto be used, theelimination of an additional five or .ten pounds is highly desirable aswill. be readily understood by those skilled in the art- In .addition,since. space is.-also at a premium in aircraft, the utilization. of asmall and compact transformer unit will. he of .great advantage.

The instant invention, therefore, contemplates a novel and improvedtransformer mounting means which is of simple construction and providesa minimum number of operations in manufacture. Thepresent inventionembodies a substantially U-shaped. bracket having a pair of flexiblearms which secure a transformer core thereto by'a flexible strap lacedthrough openings formed in the arms to engage portions of the. core. Theassembled unit'may be impregnated with suitableimpregnating material andused in that manner, and/or it may be enclosed by a casing 01- coverwhich is. fastened to the bracket and hermetically sealed.

An object :of the present invention. is to provide a novel and improvedmeans for mounting transformer cores in. asimple and efiicient mannertAnother object of the present invention: is-to provide novel means formounting transformer cores. whereby the useof bolts and screws iseliminated.

A further obiect of the present inventionis to provide a noveltransformer which is compact and light in weight.

Still another object of the .present invention is to provide novelmeansfor readily mountingtransformer cores. of. varying physical dimensions.

Still another object of the present invention is to provide a highlyimproved and novel mounting for trans former cores of thecharacterdescribed which-shall be relatively inexpensive to manufacture,positive in its operation, and practical and eflicientto high degree inuse.

Still another object is to provide a. novel andimproved method ofmounting transformer cores.

The above and other objects and advantages of the presentinvention willappear more fully hereinafter from a consideration 'of the detaileddescription which follows, taken. together with the accompanying drawingwhereintwo embodiments of the invention are illustrated.

In the drawing wherein like reference characters refer to likepartslinatheseveral views:

Figure 1 is a perspective view of the novel transformer core mountingbracket forming a part of the instant invention,

Figure 2 is a perspective view of the transformer core mounting bracketparticularly showing means for securing the core to the bracket,

Figure 3 is a sectional view of the subject matter of the instantinvention enclosed ina hermetically sealed can, and

Figure 4 is a modification of the shown in Figures 2 and 3.

Referring now to the drawing for a more detailed description of thepresent invention and more particularly to Figure 1 thereof, the instantinvention is shown as embodying a substantially U-shaped bracketgenerally designated by the reference character 11. Bracket 11 isconstructed from aluminum or any other similar ma: terial which is lightin weight, and is provided with four turned up flanges 12 extendingalonga rectangularshaped base or bight portion 13. Formed integrally with apair of opposite and parallel flanges 12 are a pair of arms 14 which areflexible in nature. The arms 14 are each arcuate shaped adjacent theirfree ends. However, it is to be understood that they may be shapedotherwise, as shown in Figure 4. A pair of extension members 15 areformed on each arm 14 and extend at right angles to the arms. Each arm14 hascut therein a slot 16 for a purpose to be described presently.

As mentioned previously, thearms 14 are flexible and may accommodate asubstantially rectangular-shaped split Hypersil type RC core 17 havingrounded sides (Figure 2'). The arms 14 are formed so that upon assemblyof the core 17 to the bracket 11 the arms are flexed to allow the coreto be centered therebetween. Extension members 15 position the core andprevent transverse movement thereof relative to thearms, while thearcuate portions of arms 14 embrace and contact the core 17 to also aidin the positioning thereof. In order to facilitate the manufacture oftransformer units, the Hypersil cores are split into two sections sothat a transformer coil winding 18 consisting of a primary coil and asecondary coil can be positioned on the core simply by inserting a legof each half of the core into a central opening formed in the coil. Itis apparent that if the cores had straight sides, the arcuate portionsof the arms 14 may be formed accordingly, to provide for the straightedges. A plurality of connecting wires 19 lead from the primary andsecondary windings of coil 18 to their 1respective terminals 20 mountedon the base portion 3.

The core 17 is secured to the arms 14 by a flexible strap 21 which islaced through the slots 16 to engage the underside of the core, andportions of the arms. The free ends of strap 21 are tightened to .theproper tension and then crimped and soldered, or fastened in any othersuitable manner, at the top of the core to securely hold the halves ofthe core to ether and to the bracket, as a single unit. The flexiblenature of arms 14' allows the arms to be wrapped about the core 17 bystrap 21 to provide for varying physical dimensions of the individualcores and to insure a properlv mounted core. Thus, the core 17 isrigidly fastened to the bracket 11 and is ready to be mounted within atransformer co er or casin 22. V

The casing 22 is recfan ularly shaped and is open at one side, or bottomthereof, to engage the flan es 12. Upon assembly of the casing 22 to thebracket 11. the casing is soldered along its bottom ed es to the flanges12 to provide an air tight seal. Air is then drawn ut of the casing byattaching sucti n means to an e haust tube 23 mounted on the base 13.When all of the air in the casing'22 is exhausted, tube 23 is pinchedand closed to' prevent entry of air into the casing and to provide ahermetically sealed transformer. It has been found advisable to addinert gases such as helium or nitrogento transfer heat from the coil 18to the casing 22. In such a case, the inert gases are addedto the casingafter the air has been exhausted, after which the tube 23 is pinchedCasing; 22 may be provided with integrally formed and. projecting lugs.24-which secure the: casing: to the chassis 25 (a fragmentary portionthereof beingtransformer mounting shown in Figure 3) of an electricalapparatus by means of threaded screws 26. This method of fastening bymeans of lugs 24 and screws 26 may be eliminated if desired, by spinningstuds in the base 13. In this manner, additional transformers may bemounted closer together to effect greater savings in space.

The aforementioned bracket construction may be changed slightly to bereadily adapted for different size and shape transformer cores. This isbest illustrated in Figure 4 wherein an E-shaned laminated transformercore 27 is secured to the flexible arms 14 by the strap 21. It is to benoted that in this embodiment of the invention, the free ends of thearms 14 are straight or meet at right angles with respect to theremaining portion of its respective arm. The position of the extensionmembers 15 and slots 16 are located closer to the base 13 to accommodatefor the greater length of the E-shaoed core 27 as distinguished from thesmaller core 17. The core 27 in this embodiment of the invention iscomposed of laminated sheets which are pressed together or clamped bythe members 15; the members 15 acting in this case to both clamp andosition the core between the arms 14. Thus, it is readily aonarent thata variety of different shaped and size transformer cores other thanshown in the drawing may be mounted by means of the instant invention.

By reason of the fore oing construction in which threaded members arenot utilized for securin the core to the casing, the mechanical life ofthe unit is len thened inasmuch as there i no danger of rivets or screwsbecoming loose due to vibration. It is to be understood that the instantinvention ma be used with or Without the transformer casin 22. The useof a tr nsformer casing has been disclosed herein to accommodate caseswhere there is dan er of corros n due to fun us or excessive humidity.It ma be readily aonreciaterl that the casing is unnecessary where suchconditions do not exist, the core and coil bein impregnated withsuitable impregnation compounds f r use in tem erate climates.

Althou h two emb d ments of he invention have been illustrated anddescribed in detail. v rious changes and modifications in the form andrelative arran ement of parts which will now a pear to th se s illed inthe art may he made without departing from the scope of the invention.

1' claim:

1. A method of manufacturing hermetic lly sealed transformers havingsubstantially rectan ular shaped transformer core s ructures. com risingthe s eps of f rming a bracket with two arms fr m a flexible material,punching cut-outs in each rm, bending the arms until they are substntially rallel and a U-shaoed member is f rmed having a bi ht portionnormal to the arms, posit oning a substantiall rectan ular sh ned corestructure between the arms and s ced from said hitzht ortion, pressingthe outer ends of the arms toward each other and into intimate cont ctwith the core structure so that the contacting end portions of the armsassume the same contour as the por ions of the core structure they contact, lacing a flexible strap throu h the cut outs in the arms and abo tportions of the core structure and arms. securin together the two endsof the strao to fixedly mount the core structure to the arms, enclosingthe arms and core structure ina casing having an open end, sealin theopen end of the casing to the bight portion, and exhausting the airwithin the casing.

2. In a transformer assembly of the class described. a transformer corehaving four sides, two of which are op ositely disposed, a substantiallyU-shaoed member made from a single piece of material and comprising a biht portion, and a pair of arms engaging said oppositely disposed sidesof said core. said bight portion being spaced from a third side of saidcore. and each of said arms having a portion arranged parallel to saidbight portion e and en aging a fourth side of said core, an apertureformed in each arm, and a strap extending throu h each aperture andengaging said arms and said third side of said core, said strap hayingends connected together for securing said core to said arms.

3. In a transformer assembly of the class described, a rectangularshaped transformer core, a member having a pair of parallel armsengaging opposite sides of said core, each of said arms having aportionat right angles to their respective arms and engaging a thirdside of said core, an aperture in each arm, and a strap extendingthrough each aperture and bearing against said arms and the fourth sideof said core, said strap having ends connected together, arranged tosecure said core to said arms.

4. In a hermetically sealed transformer of the class described, atransformer core having oppositely disposed sides, a substantiallyU-shaped member comprising a bight portion, and a pair of arms engagingsaid opposite sides, an aperture formed in each arm, a strap extendingthrough each aperture and bearing against said arms and core, said straphaving ends connected together arranged to secure said core to saidarms, and a casing having an open end and enclosing said core and saidU-shaped member, the open end of said casing being sealed to said bightportion.

5. In a transformer assembly of the class described, a transformer corehaving oppositely disposed sides and carrying a coil structure, asubstantially U-shaped member comprising a base, and a pair of armsengaging said opposite sides, terminals carried by said base forconnection to said coil structure, an aperture formed in each arm, and astrap extending through each aperture and bearing against said arms andsaid core, said strap having ends connected together, arranged to securesaid core to said arms.

6. A method of manufacturing a hermetically sealed transformer having asubstantially rectangular shaped transformer core, comprising the stepsof forming a bracket With two arms from a flexible material, punching anaperture in each arm, bending the arms until they are substantiallyparallel and a U-shaped member is formed having a bight portion normalto the arms, punching an aperture in the bight portion, securing anexhaust tube to the bight portion and communicating with saidlast-mentioned aperture, positioning a substantially rectangular shapedtransformer core between the arms and spaced from said bight portion,pressing the ends of the arms toward each other and into intimatecontact with the core so that the contacting end portions of the armsassume the same contour as the portions of the core they contact, lacinga flexible strap through the apertures in the arms and about portions ofthe core and arms, securing together the two ends of the strap to mountthe core to the arms, enclosing the arms and core in a casing having anopen end, sealing the open end of the casing to the bight portion, andexhausting the air from said casing through the exhaust tube.

7. A method of manufacturing a transformer assembly having asubstantially rectangular shaped transformer core including asubstantially rectangular shaped window with a coil structure arrangedto extend through said window and about the front and rear faces and oneside of the core, comprising the steps of forming a bracket with twoarms from a single piece of flexible material, punching an aperture ineach arm, bending the arms until they are substantially parallel and aU-shaped member is formed having a bight portion normal to the arms,positioning said core between the arms with said one side adjacent tosaid bight portion but spaced therefrom so that the coil structure doesnot contact said bight portion, pressing said arms into contact withoppositely disposed second and third sides of said core, pressing theends of said arms into contact with the fourth side of said core untilsaid ends assume the same contour as the portions of the core theycontact, lacing a strap through said apertures and between said one sideand said coil structure and about said arms, and connecting together theends of said strap adjacent said fourth side for securing said core andsaid coil structure to the bracket.

References Cited in the file of this patent UNITED STATES PATENTS1,548,733 Moody Aug. 4, 1925 1,632,101 Thordarson June 14, 19271,670,697 Treanor May 22, 1928 1,731,894 Frisch Oct. 15, 1929 1,812,748Kayser June 30, 1931 1,817,714 Shand Aug. 4, 1931 2,274,296 Hughes etal. Feb. 24, 1942 2,408,211 Hodnette Sept.-24, 1946 (Other references onfollowing page) 2,069,081 5 UNITED STATES PATENTS 2,494,350 Ehrman Mar.8, 1949 2539319 Lentz Apr. 5, 1949 Somerville Sept. 27, 1949 5 HalvorsenOct. 25, 1949 38 ,8 3

Mittermaier Jan. 10, 1950 Torsch May 19, 1953 FOREIGN PATENTS GreatBritain Feb. 28, 1933

